By Barry Mulshine, MD
Board Certified Orthopedic Surgeon
The Achilles tendon is the largest, strongest tendon in the body and when not functioning properly can significantly impair everyday activities. Disorders of this tendon include chronic degenerative changes, overuse injuries and acute complete ruptures.
The two large muscles at the back of the calf, the gastrocnemius and soleus, come together to form the Achilles tendon which courses behind the ankle and attaches to the back of the heel bone (calcaneus). When these muscles contract, the ankle plantarflexes, causing the foot to point downward. The power of this muscle-tendon unit is important for pushing off when walking and running, and is essential for rising onto the toes and jumping. Forces of 6 to 12 times body weight are transmitted through the Achilles tendon during running. When the tendon is not functioning properly, these activities will become painful or impossible.
The Achilles tendon does not have a true tendon sheath like most tendons, but instead is surrounded by a thin membrane called the paratenon that provides the blood supply to the tendon. The blood supply is poorest at the midsubtance of the tendon, located approximately at the level of the ankle joint. This is the location most prone to rupture.
Midsubstance Achilles Tendinopathy
Problems with the Achilles tendon are very common among runners. In fact, 7-9% of elite runners develop some type of Achilles pathology each year. Tendinopathy is most common for middle and long distance runners, but can occur with any running sport. It is thought that alignment and mechanical factors are to blame 60-80% of the time. These could include certain foot deformities, limited joint motion, or training errors such as overly long or intense workouts. Overuse of the tendon can lead to cumulative microtrauma which can cause a cycle of tendon tissue weakening and vascular compromise.
Initially, this presents as pain after strenuous activities, and then progresses to pain during everyday activities and even at rest. Classically, for runners this causes pain at the beginning and end of the training session. The tendon will become diffusely swollen and tender. Overtime, the tendon tissue can develop firm nodules.
This condition can usually be diagnosed on physical exam alone, although imaging studies such as X-Rays, MRI, or ultrasound are occasionally worthwhile.Non-operative treatment is successful in 70-75% of patients and is directed at relieving symptoms. It is important to correct any training errors and alignment problems. Physical therapy to improve flexibility and strength may also be beneficial.
In acute tendinopathy, controlling inflammation is recommended. Modified rest, cross-training, and icing the affected area is important. Anti-inflammatory medications may have a role for acute tendinitis, but are less helpful for chronic tendinopathy. There is controversy regarding the effectiveness and safety of various types of injections. Studies investigating injections of cortisone, sclerosing agents, and platelet-rich plasma (PRP) have not demonstrated convincing benefits.
For the approximately 25% of patients who continue to have pain despite conservative treatment, surgery may be considered. In most cases, the tendon can be debrided through a small incision or even percutaneously. This involves removing adhesions and scarring around the tendon and jump starting the blood supply to the weakened area. This is successful 75-100% of the time. If there is an area of significant damage to the tendon, more invasive surgery may be needed to reconstruct the damaged tissue.
Insertional Achilles Tendinopathy
In this condition, the area of weakening is at the Achilles insertion onto the calcaneus at the back of the heel. Most typically, this is a chronic degenerative problem and tends to affect an older, less active group of patients than midsubstance tendinopathy. This will present as pain at the back of the heel aggravated by exercise, stair-climbing or running. Often there will be pain and stiffness early in the morning. The end of the tendon may become thickened, and a firm bony spur may develop at the back of the heel.
X-Rays will often demonstrate a bone spur at the back of the heel, and sometimes a bony prominence called a Haglund’s exostosis is seen. This can rub on the tendon and thereby weaken it.
Initial treatments are non-operative and are aimed at reducing the stress on and strengthening the tendon. Heel lifts or open-backed shoes can be very helpful. Specific stretching and strengthening exercises and icing the heel are also recommended. Since this is a degenerative condition rather than an inflammatory problem, anti-inflammatory medications are not generally effective. This non-operative regimen is successful in 85-95% of patients, although it may take several months for the symptoms to resolve.
Surgical treatment may be warranted for patients who continue to have persistent pain despite six months of conservative treatment. Surgery involves removing the Haglund’s exostosis and the heel spur. Sometimes, this can be done without detaching the tendon itself and allows for early weight bearing after surgery. However, if the spur is larger, the tendon may need to be elevated off the bone and then reattached with bone anchors after the spur is shaved off. In some cases, the tendon is in such poor condition that a tendon transfer is necessary to strengthen the Achilles and preserve function.
Achilles Tendon Rupture
A complete tear of the Achilles tendon can occur if the calf muscles quickly contract while the ankle is being forced into dorsiflexion, or flexing the foot upward. This is most common in middle aged men, the so-called “weekend warriors.” Sometimes, this can occur when trying to jump, or during a slip or stumble, and at times, an audible crack or pop can be heard. The pain is usually more severe in the calf than by the ankle. Patients will often report that they thought someone had kicked or struck them in the calf. Initially, walking is difficult and painful, although the pain does gradually improve with time.
It is very important that treatment begin immediately after an Achilles rupture, so early evaluation by an orthopedic surgeon is critical. Patients who wait 4-6 weeks to seek treatment because they self-diagnosed an ankle sprain will have a poorer outcome. Acutely, the diagnosis can usually be made without an MRI, except in some equivocal cases.
The proper treatment for acute tendon ruptures is somewhat controversial. Traditionally, non-operative treatment was recommended for ruptures in older and less active patients and open surgical repair of the tendon recommended for younger, more active patients. Non-operative treatment consisting of casting and crutches for six weeks had pretty good results, but with a higher rate of repeat ruptures compared to surgical repair. Newer, non-operative protocols involving early motion and earlier weight bearing have– although counterintuitively– yielded better outcomes. In fact, some studies have shown very similar outcomes compared with surgical treatment, without the risk of wound-healing problems.
For more athletic patients desiring surgical treatment, there are newer, less-invasive techniques that reduce the risk of wound problems and allow for earlier weight bearing than traditional, surgical repair. Sutures can be placed into the tendon through puncture holes in the skin and brought together using a special instrument inserted through a small incision over the torn tendon. The sutures can either be tied together to repair the tendon or can be attached directly to the heel bone with bone anchors.
The key to obtaining good outcomes with Achilles tendon ruptures is prompt diagnosis, and quickly initiating treatment, be it operative or non-operative.
This article was published in the January-March 2015 edition of ”FYI from OCI”, a quarterly publication created by the Orthopedic Center of Illinois. To see the full publication, click HERE.